In wireless communication, radio frequency power amplifiers are used to convert a signal of relatively low power to a signal of relatively high power. With the development and evolution in semiconductor fabrication, radio frequency power amplifiers are required to meet modern design requirements, such as smaller size, higher operating band, larger power gain and wider bandwidth. Moreover, in order to enhance system efficiency and reduce production cost, it is required to integrate power amplifiers with other components, such as wireless transceivers, in the chip design.